In a food processor with a steel blade, place the flour, butter, powdered sugar, vanilla, and salt. Process until a crumbly mixture is obtained.
Add the egg and continue to process until the dough lumps are formed.
Transfer the dough to a lightly floured work surface and form a disc shape.
Wrap the dough in plastic wrap and cool in the refrigerator for an hour.
Set the oven to 180°C / 360°F fan.
On a floured surface, roll out the dough to a 3-4 mm thick sheet.
Spread the ground almond in the center of the dough.
Place the cut nectarines on it and in a spiral shape as much as possible. Note, it does not need to be too tidy.
Sprinkle 4 tablespoons of sugar on the nectarine.
Fold the dough edges onto the filling. Try to catch all of the filling and avoid any holes on the sides.
Sprinkle the last tablespoon of sugar on the dough edges.
Decorate with sliced almonds on the edges.
Bake for 20-25 minutes.
Let the dish cool and enjoy!